Brake for strand-serving apparatus



y 8, 1 2 T. T. BUNCH 2,602,282

BRAKE FOR STRAND-SERVING APPARATUS Filed July 1, 1949 I 4 Sheets-Sheet l 6/ n I 4/ I I 1 A: 23 fl 57 I I I FIG I //v VEN TOR Z 7. BUNCH July 8, 1952 T. T. BUNCH BRAKE FOR STRAND-SERVING APPARATUS 4 Sheets-Sheet 2 Filed July 1, 1949 H C R mm m W N B E 1 V W T r v v. oJ m3 B 7 NS! J x C X l: n

, &2 3 4 W 6E 8 w m2 #2 4 2 4 2? m3. A A \w A l|-1 e m NE if 8 N2 v 7 2i \\\\\A- m: o O k a l M 22 b2 ws 2 R. 2 \3 MN Q2 n 5 93 v w w- \w ATTORNEY y 8 1952 T. T. BUNCH 2,602,282

BRAKE FOR STRAND-SERVING APPARATUS Filed Juli 1, 1949 4 Sheets-Sheet 5 IN [/5 N TOR z r BUNCH BY z A TTORNE Y T. T. BUNCH BRAKE FOR STRAND-SERVING APPARATUS July 8, 1952 4 Sheets-Sheet 4 a Go INVENTOR z T. BUNCH BJ Y ATTORNEY Filed July 1, 1949 Patented July 8, 1952 BRAKE FOR STRAND-SERVING APPARATUS Tillman '1. Bunch, Ashland, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application July 1, 1949, Serial No. 102,664

18 Claims.

1 This invention relates to brakes for strand handling apparatus, and more particularly to brakes for applying tension to strands being withdrawn from supply cops and for stopping the withdrawal of such strands.

In the manufacture of the electrical conductors for use in the communication arts, certain types of conductors are advanced longitudinally through a concentric servingmachine to receive a helically applied covering of cotton or similar material. In such machines, a member revolving concentrically around the core withdraws a composite band of strand material from a supply cop positioned on a rotatable spindle, and serves it around the core.

The minimum speed of rotation of the spindle and the supply cop carried thereby due to'the withdrawal of the strands from the cop is, in some cases, substantially greater than the speed of the strand serving member. Various means have been employed in the art to apply an automatically decreasing braking force to a cop so as to maintain constant tension on the strands as the serving operation proceeds from a full cop to an empty cop. However, heretofore no braking apparatus has been developed, which is designed to apply a substantially increased braking force to stop the cop simultaneously with the serving member when the serving member is stopped because of a broken strand or other defacts in the serving operation.

An object of the invention is-to' provide new and improved brakes for strand handling appa-, ratus.

Another object of the invention is to provide new and improved brakes for applying tension to strands being withdrawn from supply cops and for stopping the withdrawal of such strands.

A brake for strand handling apparatus which embodies certain features of the invention, comprises a rotatable spindle designed to carry a cop containing a supply of filamentary material, means for withdrawing the filamentary material from the cop and cause rotation of the cop, and braking means for retarding the rotation of the cop and spindle with a braking force correspond- 'it is withdrawn from the cop.

A clearjunderstanding-of the invention will be had'in the following detailed description of a specific embodiment thereof, when'read in conjunction with theappended drawings, in which: j Fig. 1 is a front elevation of a concentric type serving machine embodying certain features of the invention;

Fig. 2 is an enlarged fragmentary, sectional view of a portion of the apparatus shown in Fig. 1;

Fig. 3 is a vertical, sectional view taken along line 33 of Fig. 1;

Fig. 4 is horizontal, sectional View taken along line 44 of Fig. 2;

' Fig. 5 is a horizontal, sectional view taken along line 55 of Fig. 2;

Fig. 6, is an isometric view showing a halfsection of a cop tube used with the apparatus shown in Fig. 1 in the manner shown in Fig. 4; Fig. 7 is a vertical section taken along line 1-1 of Fig. 2, and

Fig. 8 shows a schematic wiring diagram of the electrical apparatus used to control the serving machine shown in Fig. 1, and also a schematic diagram of a compressed air circuit controlled by the electrical apparatus.

Referring now to the drawings and more. particularly to Fig. 1,'there is shown a concentric type strand serving machine which is arranged to operate in a vertical position and includes a heavy base In which is suitably secured to the floor and a shaft indicated generally at ll suitably journalled in anti-friction bearings positioned in the base I0. The lower end of the. shaft II is arranged to receive a pulley [2 which engages an endless belt 15, which belt in turn engages a pulley l6 driven by a motor 20. A cup 22 is secured to the upper end of the shaft II for rotation therewith and has a cop 23 positioned on a spindle 2i rotatably mounted on a portion of the spindle extending into the cup. The cop23 contains two composite textile bands 24-44 wound thereon 180 apart in a predetermined pattern which permits easy withdrawal of the bands from the cop. Each band 24' contains a plurality of individual strands and is withdrawn from the cop and passed through a slot 21 provided in the cup 22, after which the individual strands 25-25 of the band are fanned out and pass around individual guides 2828 secured on the cup to a strand guide 30 provided on the upper end of the shaft II which extends above the spindle 2|. When the cup 22 is rotated by the motor 20, it withdraws the bands 2424 from the cop and wraps the individual strands 252 5 thereof around a core 3| being advanced through a central bore 32 provided in the. shaft II by a The core 3| (Fig. 1), after receiving the textile covering, shall be referred to as the insulated core 34. The core 3| is withdrawn from a supply reel 35, which is rotatably mounted in a suitable manner, and passes around an idler pulley 36 mounted on a heavy arm 3'! pivotally mounted on the base It, and a pulley 3B which directs the core 3! to the central bore 32 of the shaft H. The arrangement of the pulley 38 on the heavy arm serves to maintain substantially uniform tension on the core 31 by cushioning the jerks on the core caused by variations in the unwinding diameter of the reel. The core 3! passes upwardly through the bore 32 of the spindle ll and,

receives a textile covering at a point'adjacent to the guide 3% to form the insulated core 34. The core 34 advances upwardly through a central bore 40 provided in a tubular cop storage post 4| which is held in a vertical position by a tubular postAZ secured to the base It in a suitable manner and around a pulley 43 to the capstan 33. After passing around the capstan several times, the insulated core 34 passes directly to a pulley 59 mounted on a suitable traversing apparatus 51 which serves to distribute the core 34 evenly on a takeup reel 52 rotatably mounted on a support 53 and driven by a motor 555.

A plurality of cops like the cop 23 (Fig. l) are positioned in tandem over the cop storage post 4| so that the core 31 passes through the center aperture thereof in order that a full cop may be positioned on the spindle 2! when the cop originally positioned thereon is exhausted. A tubular member 5'! is slidably positioned in thebore 40 of the post M and normally has a portion thereof which extends below the free end of the post 4| and passes through the central aperture of the lowermost cop 23 and thereby holds it in line with the advancing core 34. The member 51 is connected to a similar member ts slidably positioned in the tubular post 42 by means of a cable 6!. An arm E2 is hingedly mounted on the post 42 and is normally positioned to support the lowermost cop'23 a predetermined distance above the .top ofv the cup 22. A second arm 63 is hingedly mounted on the post 42 for supporting the remainder of the cops .23-23. stored on the post 4!. A pin. 65 is secured to the member 65 and operates within a longitudinalslot 66 provided in the post 42. The member'El is designed to be heavier than the member (ill, in which case, the member 5? positions itself in the post 4! by its own weight so that the lowermost end thereof is adjacent to the guide St. The pin 65 normally is positioned at-the top of theslot 66 and by moving the pin downwardly to thebottom or the slot, the member 51 may be'withdrawn from the lowermost cop and positioned entirely within the post 4|.

The cup 22 rotates within a cylindrical housing 10 secured on the base l9 and provided with anarcuate sliding door ll made of transparent material and arranged 'tobe operable by the lever 12. A sensitive detector indicated generally at is provided in the housinglll for the purpose of stopping the cup 22 when one of the strands -25 breaks and also when the cop 23 is exhausted; The detector 15 includesv an upright post 16 rigidlyisecured to the base l0 (Fig.

2), and a rod lf'l rotatably mounted between supports spacedly secured to the post 16 one of which is indicated bythe .numeral'lB (Fig. 5 The ends of the rod'll are provided with ball bearings, one of which is shown in Fig; '7 andindicated by the numeral 19. Each bearing T9 is positioned on a conical seat provided in a counterbore provided in each support so that the post may be turned by the application of very little force.

A cam St is secured on the end of the rod ll adjacent to the support 18. The cam 80 is made of a tubular member having. one side thereof fiattenedto engage a resilient operating arm 8| of a sensitive switch 82 which is secured on the support 18. A wire loop 86 is secured to the rod Tl in such a position that when the fiat side ofthe cam 80 is in contact with the resilient arm 8|, the wire loop 88 is positioned directly in the path of any of the strands 2525 which break while they are being served on the core 3!. When any of the strands 25-25 break while the cup is serving the strands in the core 3|, the loose end of the broken strand hanging from the guide 38 flies outwardly due to centrifugal force acting thereon and strikes the wire loop 3'6 with sufficient force to turn the rod H in a clockwise direction as viewed in Fig. 5; This movement of the rod Tl actuates the resilient arm 3! suificiently to operate the switch 82' which is electrically connected to immediately stop the cup 22 in a manner hereinafter to be described.

While the detector '55 is so arranged that a single strand will turn the rod 1?," it must beso adjusted that it will not be operated inadvertently by the vibration of the apparatus or by the windage created by the revolving cup.

Air under pressure, from a suitable supply (not shown) is conducted by a pipe Sllto a pressure regulating valve 8| from which the air under pressure passes to a solenoid-operated valve 92 and from the solenoid valve through a pipe 93 to an air control unit indicated generally at 95.. The air then is directed from the air flow control unit 95 by a pipe 9'! to a brake mechanism for the spindle 2 I. l

The air flow, control unit 95. comprises an air valve Hi0 mounted in. an inclined position in a generally rectangular housing llll so that a por tion of the valve stem- H32 thereof is positioned outside the housing to-receive a hand wheel I03.

A wheel IE5 is keyed to a portion ofthe valvestem positioned within the housing lfll and is provided with a ring, I66 about the periphery thereof which is madeof rubber or other suitable frictionmaterial. A small synchronous motor I09 and gear unit I I I3 is secured to a support I I l pivotally mounted on a bracket H2 secured to the topof the housing. I01. The output shaft of the gear unit i In is provided with a drive pulley |l5 which rests against the ring I06. provided on the wheel Hi5. When theimotor [Bills energized, it rotates the pulley '5 which, in. turn, drives the wheel IE5 and thereby. turns the valve stem I02 to change the opening of the valve :00. The hand wheel I53 assumes the full line positionshown in Fig. 3 when the valve Illil is fully open. As the wheel IE5 is turned by the motor.- lce theshaft moves inwardly, in the valve-I80, and when the hand 'wheel I03 assumes the broken line position, the valve lllllis fully closed.

A cover] ll encloses the motor I 09 and is held in place on the housing llll by a nut m which threadedly engages the end of a "post lzfl secured in the housing-I01 V v 1 V 1 Referring to Fig. 2,-it isn-oted that a ballbear;

ing i 9 22 is. positioned between 7 the upper end of. the shaft H and. an annular support l23 which islsecuredto the base 1;; An annular member l251is ke'yedto the shaft for rotation therewith and has the upper face-thereof undercut to receive the bottom of the cup '22 and tojalignthe cup coaxially with the rotating axis of the shaft. The bottom of the cup 2 2 is secured between the upper face of the ring 12-5 and an annular cap 126 by a plurality of screws like the screw 121. The upper end of the shaft 11 is provided with a reduced body portion 128 which extends upwardly in the cup and has the spindle 21 rotatably mounted thereon by means of needle bearings like the needle bearing 129.

The spindle 21 consists of a tubular body portion 136 which engages the needle bearings 129-129 and a hub portion 131 .formed integrally'therewith. The tubular body portion 136 of the spindle is provided with a plurality of longitudinal grooves 132-132 equally spaced about the periphery thereof and is designed to slidably receive a cop tube indicated generally at 133 on which the cop 23' is wound. The cop tube 133 is formed of two identical, elongated sections 134-134 of semi-circular cross-section one of which sections is shown in Fig. 6. Each section 134 of the cop tube is provided with an inwardly projecting longitudinal rib 131 centrally disposed between the edgeszthereof and an inwardly projecting rib 138 at 'each edge thereof. When two sections 134-134 are butted together to form the cop tube 133, the ribs 131-131 slidably engage the grooves 132-132 of the spindle 21 and the ribs 138-138 have a combined width which permits them to slidably engage diametrically opposed grooves in the spindle 21 when the cop 23 is positioned on the spindle (Fig. 4).

V The cop tube 133 is designed to have an internal diameter larger than the diameter of the tubular body portion 136 of the spindle 21, in which case, the ribs 131-131 and 138-138 secure the tube 133 concentrically on the spindle 21 so as to leave an annular clearance between the spindle and the internal surface of the tube. The ribs 138-138 secure the sections 134-134 on the spindle 21 against transverse movement, in which case, the sections can not be separated until the cop tube is slid off the upper end of the spindle. The ribs 138-138 also are designed to hold the sections 134-134 on the spindle against the action of centrifugal force on the sections when the spindle is rotated by withdrawal of the bands 24-24 from the cop 23 by the cup 22.

The hub 131 of the spindle 21 is of such diameter that a predetermined minimum running clearance 141 is provided between the internal bore of the cap 126 and the periphery of the hub 131. The hub 131 has a flange 142 formed integrally therewith which is positioned in a counterbore 145 provided in the annular member 1 25.

The counterbore 145 is of such diameter that a minimum running clearance 146 is provided between the periphery of the flange 142 and the counterbore 145. The underside of the flange 142 is provided with an annular groove 141 which is designed to receive a ring 148 made of felt or other suitable friction material. The spindle 21 is assembled on the upper end 128 of the shaft 11 with the needle bearings 129-129 so that the riphery of the member125, whereby air from the pipe 9'1 passes into the groove 1-52 and-ups wardly through passages 155-155 into an annu lar chamber 156 provided between the underside of the cap 126 and the top surface of the flange 142 of the spindle 21. Minimum clearances, while not indicated in Fig. 2 of the drawings, are provided between the annular member and the ring 151. A grease seal 166 is positioned in the counterbore 161 provided in the hub 131 of the spindle 21 and a plurality of springs 162-162 are positioned between the grease seal 166 and a cup-shaped ring 163' resting on a shoulder 164 provided on the shaft 11. The springs 162-162 are designed to offset some of the weight of the spindle 21 and the cop 23 so that the felt ring 148 bears against the bottom of the counter: bore of the driving member 125 with a predetermined force when the cop tube 133 is empty and exerts a braking force on the spindle when it is rotated by the withdrawal of the strands from the cop 23. When air is admitted to the annular clearance 156, in a manner hereinafter to be described, it forces the spindle downwardly and presses the ring 148 more forcibly against the bottom surface of the counterbore and thereby increases the braking force exerted on the spindle by the ring 148. Since running clearance is provided between the periphery of the flange 142 and the counterbore 145, a certain amount of the air admitted to the annular chamber 156 leaks through this clearance to the undersideof the flange 142 and must be allowed to escape freely from this area in order to prevent it from interfering with the braking force exerted on the spindle by the ring 148. A plurality of holes 165-165 are provided around the hub 131 to permit this air to escape from the underside of the flange 142. The ring 163 is keyed for rotation with the spindle 21 by means of a pin 166 which is positioned in one of the holes 165 so that the inner end thereof engages a complementary recess provided in a portion of the ring 163 between the springs 162-162.

Fig. 8 shows a schematic wiring diagram for the electrical apparatus forming a part of the above-described serving machine in which terminals 116-116 may be considered as being connected to a suitable source of three-phase A. C. voltage. The motor 26, which drives the shaft 11 and the cup 22 secured thereto and the capstan 3 3 is connected across the terminals 116-116 in series with normally open contacts 111-111 provided on a contactor 112 and nor- .mally open contacts 114-114 provided on a second contactor 115. A resistor 111 is connected across each normally open contact 114. A threephase solenoid indicated generally at 186, which is provided for operating the brake (not shown) of the motor 26, is connected directly across the terminals 116-116 in series withnormally open contacts 181-!81 of a relay indicated generally at 182.

The electrical apparatus for controlling the operation of the motor 26 and the solenoid 186 receives potential from busses 185 and 186which are connected across .the outside terminals 116-116 of the three-phase voltage supply. A step down transformer 181 has its primary winding 188 connected directly across the busses 185 and 186. The secondary winding 196 of the transformer has one side thereof connected directly to ground indicated at 191 and the other side thereof connected to ground 191 in series with a normally closed contact 192 of thesensih"? swith 2 0 h vd r 15, a normally tothe bus I35 in series with a normally open start contact 98 and a normally closed stop contact 256, and has the other side thereof connected to the bus I86 in series with a normally open contact 2M provided on the relay I95. A normally open contact 262 is provided on the relay I15 and is connected in parallelwith the start contact I98. An operating coil 255 of the relay I15 is connected to a junction 2% provided in the connection between one of the contacts I1-!-I1I and one of the contacts I14-I14. The other side of the operating coil 265 is connected to the bus ltd in series with a normally open contact 201 provided on a, time delay relay 2 I and anormally open contact 2i! provided on the relay I12.

An operating coil 2I2. of the relay 210 has one side thereof connected to the bus I85 in series with a normally open contact 2I3 provided on the relay I and has the other side thereof connected to the bus I in series with the contact 2II of the relay I12. A junction point 2I5 provided between the contact H3 and the coil 2I2 is connected to a junction point 2I5 provided between the start contact I98 and the stop contact 206, in which case, the start contact I98 is connected in parallel with the'contact 2I3 of the contactor 15. An operating coil 2I1 has one side thereof connected to the junction 2I5 and the other side thereof connected directly to the bus I85. A solenoid 228, which is arranged to actuate the valve 92 has one side thereof connected to the bus I85 in series with a normally closed contact 22I of the sensitive switch I2I positioned in the control unit 95 and the other side thereof connected to the bus I86 in series with a normally closed contact 222 provided on the relay I82 and a normally closed push button contact 223. The motor I In of the air flow control unit 95 has one terminal thereof connected to the bus 35 in series with the contact iii and the other "terminal thereof is connected to a reactance coil 225, which in turn, is connected to a junction point 221 provided in the connection between one of the contacts Ill and one of the contacts I14- of the relays I12 and I15, respectively.

The compressed air circuit for the serving machine also is shown schematically in Fig. 8 to correlate its operation with various electrical apparatus described in the wiring diagram. When the motor is energized to rotate the cup 22, the

solenoid 223 is deenergized and closes the valve Operation Let itbe assumed that a cop 23 is positioned on the spindle 2i and that the cops 2323 have been assembled on the post 8| as shown in Fig. l.

.A' core 3i is withdrawn from the supply reel 35 and passed around the pulleys 36 and 3 1 and M then-upwardly through the central bore 32 proseries with the resistors I11I11.

a eoa'css 8 vided in the shaft II and through the central bore of the post H and around the pulley 43, around the capstan 33 several times to the pulley 56, to the takeup reel 52. When the core 3| has been threaded through the machine in this manner, each textile band 24 of the cop 23 is passed through its respective slot 21 in the cup 22, after which the individual strands.25-25 of each band are separated and pass around indi-- vidual strand guides zit-28 to the guide 39 provided on the upper end of the spindle M. The ends of the individual strands 2525 are, attached to the core 3I in a suitable manner. After the strands 25-25 of the bands 24-24 are secured to the core in this manner; the door 1!. isclosed, which in turn, actuates the normally open contact 93 to its closed position. When the contact I93 is closed, the Operating coil I94 of the relay I35 is connected across the secondary winding [950i the transformer I81, invwhich case, the relay is energized and closes the normally open contact 20 I.

Air under pressure is admitted to the pipe 93 and the valve 9! is adjusted to fix the air pres,- sure at the desired value for the machine, Since the contacts 222 and 223 are closed, the solenoid 22 5 is energized and holds the valve 32 open, whereby the air under pressure passes through the valve .92 to the valve we of the air fiow control unit 35 to the annular chamber I56 provided between the cap I25 and the flange I42 of the spindle 2 I.

Assuming that afull size cop 23 is positioned on the spindle 2|, the hand wheel IE3 i turned to positionv the valve I88 in its full open position, which is the full line position of the hand wheel m3 andthe wheel I35 as shown in Fig. 3. When these adjustments. have been made, the start contact I98 is actuated to its closed position, whereby the operating coil. I31 of the relay I12 is connected across the busses I and I86. Energization of, the coil I31 closes the normally open contacts I1I-I1I, which in turn, connect the motor 23 across the terminals, I'm-I10 in upon thecoil H2 is energized and closes its normallyopen contact 2il1 after a predetermined period of time has expired. The closed contact 201 connects to the coil 255, the junction 2'06, and the bus I36, whereupon the coil 265 is energized and closes its normally open contact I14I14 and 2 E3. The closed contacts I1':lI 14 shunt the resistors I-I-7I 11 from the-motor circuit, whereupon full voltage is applied to'the motor and it accelerates to full speed and in turn drives the cup 22 and the capstan 33 at full speed. As soon as the coil 205 of the relay I15 is energized to close the contact 2I3, the operating coil 2I2 is connected .directly to the bus I85, whereupon the start button may be released. When the start button I973, was actuated to its closediposition, the coil 211 of the relay I82 was energized simultaneously with thelcoil I91 of the relay I112, in whch case, the solenod IBiLof. themotor 20 was energized'torelease the brake at the same in- Since the resisters are connected in the motor circuit, the

stant that the relay I12 was energized to connect the motor 20 across the terminals I10-I'I0. The solenoid I80 remains energized to hold the brak in its off position so long as the motor remains connected to the supply terminals II-I by the contacts I'II-I'II of the relay I12.

As soon asthe relay I12 is energized to close the contacts IIII'II, the motor IIO of the air flow control unit 95 is connected across the busses I85 and I86, in which case, the motor I I0 is energized simultaneously with the motor 20. Therefore, as the motor rotates the cup to serve the textile strands on the advancing core 3I, the motor IIO turn the valve stem I02 slowly in a direction which decreases the opening of the valve I00. Since the contact 222 is opened upon th energization of the coil 2II of the relay I82, the solenoid 220 is deenergized when the motor 20 is energized and the valve 92 remains closed. As a result, air under pressur is not admitted to the air flow control unit 95 or the annular chamber I 56 provided at the base of the spindle 2 I. Under these conditions the braking force of the ring I48 tending to retard the rotation of the spindle caused by the withdrawal of the strands from the cop carried thereby is due entirely to the weight of the cop plus the fixed weight including the weight of the cop tube I33 and the spindle 2 I.

When the serving operation commences with a full cop positioned on the spindle, the braking force applied to the spindle is directly proportional to the weight of the cop becaus the weight of the tube and the spindle i insignificant with respect to the weight of the cop 23. In other words, under these conditions the weight of the cop 23 bearing on the felt ring I 40 sliding around the bottom of the counterbore I45 of the annular member I determines the tension produced in the strands 2525 as they are served around the core 3| by the cup 22. The diameter of the cop 23, at the start of the serving operation produces a maximum leverage condition as the strands are withdrawn from the cop, and as a result, the braking force of the ring I48 tending to retard the rotation of the cop with respect to the cup, must be at its maximum value in order to provide a predetermined serving tension in the textile strands 2525. The weight of the cop at the start of the serving operation is as its maximum value, in which case the pressure that the cop exerts downwardly on the friction ring I48 provides a braking force which is commensurate with the weight of the cop and thereby creates the required tension on the strands 2525 at the start of the serving operation.

As the cup is rotated to withdraw the textile bands 24-44 from the cop 23 and serve them spirally around the core 3I to form the insulated core 34, the diameter of the cop is constantly decreasing and likewise, the lever arm at the point of the withdrawal of the strands is constantly decreasing.

Due to the fact that the lever arm of the unwinding diameter of the strands being withdrawn from the cop is constantly decreasing, it is necessary that the braking force exerted on the spindle by the ring I48 constantly decrease in proportion to the change in th lever arm in order to maintain uniform tension on the strands 2525. As the strands are withdrawn from the cop 23, the downward pressure exerted on the ring I48 by the weight of the cop constantly is decreasing with the result that the braking force on the spindle consequently is decreasing. By virtue of this arrangement, the braking force on the spindle 2I 10 decreases by an amount corresponding to the decrease in the weight of the cop 23 so that the tension on the strands 2525 remains substantially uniform during the serving operation from a full cop to an empty cop.

When the size of the cop 23 is reduced to a point where the weight of the cop tube I33 and the weight of the spindle 2| exceeds the weight of the remaining portion of the cop 23 left on the cop tube, the downward pressure exerted on the ring I48 is determined by the combined weight of the cop and the spindle. The combined weight of the cop tube and spindle is a fixed value and does not change as the cop diminishes in size. The springs I02I62 positioned under the spindle ofiset a predetermined portion of the combined weight of the spindle and cop so that the weight of the cop 23 controls the tension on the strands 2525 throughout a major portion of the serving operation. When the effective weight of the tube and spindle on the ring I 48 due to the springs I02--I62 exceeds that of a partially exhausted cop 23, the effective weight produces a downward pressure on the ring I48 which creates a tension on the strands 2525 equal to the tension produced by the weight of the cop at e the start of the serving operation. The cup continues to withdraw the strands from the cop 23 and serves them around-the advancing core 3| until a loose thread, which was placed in the cop 23 when the cop was wound on the tube I33, is uncovered and flies outwardly due to centrifugal forcev and strikes the wire loop 88 of the detector I5. The loose thread strikes the loop with sufficient force to turn the rod TI and cause the resilient arm 8I to actuate the operating button-of the sensitive switch 82 and open its normally closed contact I92.

When the contact I92 is opened, the, coil I94 is disconnected from the secondary winding I90 of the transformer I81, whereupon the coil is deenergized and allows the contact 20I to drop open. The opening 'of the contact 20I disconnects the coil I91 from the busses I85 and I85, whereupon the relay I12'drops open and deenergizes the relay II5 which in turn deenergizes the relay 2I0. As a result, the motor 20 and the solenoid I aredeenergized to stop the motor-and the cup 22 immediately. When, the coil 2I'I is deenergized, the contact 222 recloses and connects the solenoid 220 to the bus I80. However, the motor I I0 of the control unit 95, which was energized simultaneously with the motor 28, is arranged to close the valve I00 before the cop 23 is completely exhausted because when the cop is nearly exhausted the braking force on the spindle due to its weight is sufficient to stop the spindle 2I and prevents overrunning of the spindle with respect to the cup 22. Therefore, when the loose strand of an exhausted cop strikes the wire loop 88 and actuates the switch 82, the motor I I0 has turned the wheel I05 to close the valve I00 and opens the contact 22I of the sensitive switch I2I. The opening of the contact I20 disconnects the solenoid 220 from the busses I and I86 and allows the solenoid valve 92 to open before the contact 222 is reclosed. Since the valve I00 of the air flow control unit is fully closed before the valve 92 is allowed to open air under pressure from the solenoid valve 82 is not admitted to the annular chamber I58 when a loose thread strikes the wire loop 05 and actuates the switch 82. Therefore, the braking force exerted on the spindle 2| bythe rin I08 due to its own weight, stops the spindle which is rotating substantially faster. than the 11 cup 22 practically simultaneouslywith-the cup, whereby no overrunning of the spindle occurs with respect to the cup.

When the motor is stopped by the brake, the capstan 33 is also stopped and the core 3| is not advanced through the shaft l I and the-strand guide 38. The tube lit is slid off the end of the spindle andsepa-rated so that it may be'removed from around the core 31. Thearm 62 is moved out of position so that the'lowermost cop 23 positioned on the post 41 may be lowered into the cup'ZZ and positioned on the spindle 2| as shown in'Fig, 4. When this cop 23 is positioned on the spindle, the start button 198 is actuated to start the motor 2!! and place the serving machine in operation in the manner described. This cop is served around the core 3-! untilthe loose thread provided in the cop terminates the operation of the cup in the manner described hereinabove.

While the detector 15 serves to terminate the operation'of the serving machine when the cop from which the textile bands are being withdrawn is nearly exhausted, the switch also acts to terminate the operation of the'machine when one or more of the strands -25 break during the serving operation in the-following manner:

Let it be assumed'that a-cop 23 is positioned on the spindle 23 and that the motor has been energized to rotate the cup and withdraws the bands 25524 from the-cop and serve the strands 25-25 around the advancing core '3 I. When the machine is operating in this manner, the solenoid 22B is deenergized and the valve 92 is closed so that air under pressure from the pipe 9| is not admitted tothe air flow control unit 95. Under theseconditions the weight of the cop 23 exerts sufficient *force downwardly on the ring M8 to maintain a predetermined tension on the strands 25%25 :as they are served on the advancing core.

Let it be further assumed that one of the -strandsi2525 breaks after the machine has been in operation for a very'short period of time with respectto that period of time-required to serve a full :cop on the core :31. Abroken strand causes an imperfect serving on the core 3| and the machine must be stopped immediately after a break occurs in order that the loose ends of the broken strands maybe tied together so that the remaining :portion of the cop may 'be served on the coret31.

When one or the strands breaks, the cop 23 is rotating substantially faster than the cup 22 and is of'such weight that a substantially greater braking force is required to-stop thecop 2'3 simultaneously with the cup 22 to-prevent overrunning of the cop.

From the time the serving operation was commenced until the break occurs in one of the strands, the motor H0 turns the valve stem I02 in a direction which gradually decreases the opening of the valve I160. The speed of rotation of the pulley '5 together with the diameter of the driving wheel 105 is arranged to turn the valve stem 162 at .a ratewhich produces a decrease in the opening of the valve H10 in proportion to the constantly decreasing size and weight of the cop :23. When the strand breaks, it flies outward- 1y,3in much the same manner as that described for the loose strand attached near the inner end of the cop, and strikes the wire loop 88 with sufiicient force to turn the red I! and actuate the operating button of the switch 82 to open its normally closedcontact I92 and deenergize the coil 1 94 of the relay I95.

As soon as thecoil I94 is deenergized the contact 20! drops open and deenergizes the relays I12, H 5 and E82 to immediately stop the motor 2&3 as described. The contact 222 reduces and energizes the solenoid 2213 which opens the valve 92 to admit air under pressure to the air :fiow control unit 95. Since the valve its is partially closed by an amount proportional to the decrease in the initial size of the cop 23, the air flow control unit admits air under pressure to the annular chamber I56 at a rate which builds up a pressure therein to increase the downward pressure on the ring Hi8 and thereby increases the braking force on the spindle 2| sufiiciently to stop the spindle 2i and cop '23, carried thereby, simultaneously with the cup 22.

The pressure of the air admitted to the annular chamber I56 by the valve Hit! is arranged to be supplied by the valve use at a rate which will exert sufiicient pressure against the flange Hi2, while some of the air is escaping through the predetermined clearance l li provided between the hub 53% and. the internal bore of the capstan I26. The clearance M! is designed to allow the air to escape from an annular chamber I56, at a predetermined rate of flow. The initial pressure of the air admitted/to the valve Hi0 together with the size of the valve opening at the time one of the strands 25 breaks, is designed to admit air under pressure at a rate which is substantially greater than that at which it can escape from the annular chamber 15,, so that the braking force on the spindle 2i will increase in accordance with the size of the cop to be stopped when the strand breaks.

Some'oi the air admitted to the annular chamber !56, when a broken strand occurs, escapes to the underside of the flange Hi2 of the spindle around the clearance M6 between the periphery of the flange and the counterbore Hi5 provided in the rotating member 125. To prevent this air which escapes to the underside of the flange M2 from'interfering with the operation of the brake, the air is allowed to escape therefrom through a plurality of passages tort-4215 provided in the hub l3i of the spindle.

While one or more of thestrands 25- 25 may break at any time during the serving operation from a full cop to an empty cop, air under pressure is admitted to the annular chamber I56 at a rate which creates air pressure therein commensuratc with the size of the cop to be stopped simultaneously with the cup 22. The size of the cop 23 at the time the strand breaks determines the air pressure required to stop the .cop, and since the opening of the valve !02 is constantly decreasing in size in proportion to the decrease in the size of the cop, the valve always is adjusted so that it admits the air under pressure to the annular chamber I56 at a rate which will provide the necessary pressure on the brake to stop the cop simultaneously with the cup. By controlling the rate of flow of air under pressure to the annular clearance'in this manner,

' the additional braking force applied to the spindle spindle, which may cause serious tangling of the ily modified and adapted to suit various types of apparatus, where it is desirable to prevent'overrunning of a rotating member from which one or more filamentary strands are being withdrawn at a substantially high rate of speed, without departing from the spirit and scope of the inven tion.

What is claimed is:

1. An apparatus for tensioning strand material being withdrawn from a supply cop, which comprises a vertically positioned shaft, a spindle rotatably mounted on the shaft and designed to carry a cop containing a supply of strand material, means' rotatable about the shaft for withdrawing the filamentary material from the cop and cause rotation of the cop, means for rotating the strand withdrawing means at uniform speed, a brake elementmounted on the spindle for retarding the rotation of the spindle with a braking force determined by the weight of the cop and the spindle and thereby maintaining a substantially uniform tension on the material as it is expended from a full cop to an empty cop, a detector positioned adjacent to the rotating cop and arranged to be actuated by the end of a broken strand carried by the withdrawing means, and means responsive to the operation of the detector by a broken strand for stopping the means rotating the withdrawing mears and thereby terminate the withdrawal of the strand from the cop.

2. An apparatus for tensioning strand material being withdrawn from a supply cop of strand handling apparatus, which comprises a vertically positioned shaft, a spindle rotatably mounted on the shaft and designed to carry a oop containing a supply of strand material, rotatable means for withdrawing the filamentary material from the cop and cause rotation of the cop, means for rotating the strand withdrawing means, a brake element mounted on the spindle for retarding the rotation of, the spindle with a braking force corresponding to the weight of the cop and the spin- 7 le and thereby maintaining a substantially con stant tension as the material is expended from a full cop to an empty cop, a post rotatably mounted adjacent to the cop and having a wire loop thereon extending generally opposite to the direction of rotation of the cop, and a sensitive switch arranged to be actuated when the post is turned to stop the means rotating the strand wihdrawing means, said post being sop ositioned that an end of a broken strand carried by the withdrawing means, said post being so positioned suflicient force to turn the post and actuate the sensitive switch and stop the withdrawal of the strand from the cop.

3. An apparatus for tensioning strand material being withdrawn from a'supply cop of strand handling apparatus, which comprises a vertically positioned shaft, a spindle rotatably mounted on the shaft and designed to carry a cop containing a supply of strand material, means rotatable with respect to the cop for withdrawing the strand material from the cop and cause rotation of the cop, means for rotating the strand serving means to a uniform speed, meansfor applying a braking force to the spindle corresponding to the 14 weight of the cop and the spindleso as to maintain a substantially uniform tension on the material as it is withdrawn from the cop, means arranged to be actuated by the end of a broken strand for stopping the means rotating the strand serving means, and means for increasing the braking force applied to the spindle to stop the rotation of the spindle simultaneously when the serving means is stopped by a broken strand to prevent overrunning of the cop with respect to the serving means.

4. An apparatus for tensioning strand material being withdrawn from a'supply cop provided on strand handling apparatus, which comprises a vertically positioned shaft, a spindle rotatably mounted on the shaft and designed to carry a cop containing a supply of strand material, means rotatable about the axis of the cop for withdrawing the strand material from the cop and cause rotation of the cop, means for rotating the strand withdrawing means at a uniform speed, a brake element provided on the spindle for retarding the rotation of the spindle as the strand material is withdrawn therefrom, said spindle being movable axially on the shaft so that the brake element applies a braking force to the spindle corresponding to the weight of the cop and spindle and thereby maintains a uniform tension on'the strand material as it is expended from the the cop, a detector positioned adjacent to the rotating cop and arranged to be actuated by the end of a broken strand, means responsive to the operation ofthe detector by a broken strand for stopping the means rotating the strand withdrawing means and thereby terminate the withdrawal of the strand material from the cop, and means for causing a fluid under pressure to urge the spindle downwardly on the shaft to increase the braking force exerted by the brake element on the spindle by an amount corresponding to the size of the cop to be stopped when the serving means is stopped by a broken strand in order to prevent overrunning of the cop with respect to the serving means. 5. An apparatus for tensioning a strand material being served around a continuously ad vancing core, which comprises a shaft vertically positioned adjacent'to the advancing core, a spindle rotatably mounted on the shaft'and designed to carry a cop containing a supply of strand material to be served around the core, means rotatable about the axis of the core for withdrawing the strand material from the cop and serving it spirally around the core and cause rotation of the cop, means for rotating the strand serving means at a uniform speed, a flange secured centrally on the shaft and having an annular chamber formed therein, said spindle having a flange secured thereon for rotation within the annular chamber, a brake element provided on the flange of the spindle so as to slidably engage the bottom of the annular chamber, said spindle being movable axially on the shaft so that the brake element retards the rotation of the spindle with a braking force determined by the weight of the cop and spindle and thereby maintains uniform tension on the strand material as it is expended from a full cop to an empty cop, a post rotatably mounted adjacent to the cop and having a wire loop thereon extending toward the copymeans including a sensitive switch arranged to be actuated when the post is turned to stop the means rotating the strand serving means, said post being positioned'so that an end of a broken strand carried by the serving means strikes the. wire loop withisufiicient force to turn the post and actuate the sensitive switch to terminate the withdrawal of the strand from the cop, and means for admitting a fluid under pressure into the an.- nular chamber soas to-exert a pressure on thelupper surface of the flange on the spindleto increase the downward pressure on the brake element by an amount corresponding to the size of the cop to be stopped to stop the cop and spindle when the serving means is stopped by a broken strand in order m prevent over-running of thecopwith respect to the strandserving means.

6. An apparatus for tensioning strand material being served around a continuously advancing core, which comprises a hollow shaft vertically positioned so that a core may be advanced therethrough, means for rotating the shaft, a spindle mounted on the shaft and designed to carry a cop containing a supply of strand material to be served around the core, means secured for rotation with the shaft for withdrawing the strand material from the cop and serving it spirally aroundthe advancing core and for causingrotation of the cop'at a rate of speedsubstantially greater than the speed of the serving means, means for applying a braking force to the spind-le corresponding to the weight of the cop and the spindle so as to maintain a substantially constant tension on the material as it is withdrawn from the cop by the serving means, and means arranged to be actuated by a broken strand being carried around the core by the serving means for stopping the shaft rotating means, whereby the serving means is stopped when a strand breaks while it is being served on the core.

7. A broken strand detector for strand handling apparatus having a strand supply cop and rotating means for withdrawing the strand from the cop, which comprises a post rotatably mounted adjacent to the withdrawing means, an electrical circuit including means for controlling the rotating means withdrawing the strand from the cop, a sensitive switch positioned adjacent to the post for controlling the continuity of the electricalcircuit, and means secured on the shaft for actuating the switchv-Jhen the shaft is turned, and means provided on the shaft so as to be engaged by. the end of a broken strand and turn the shaft, whereby the switch is actuated to effeet a change in the electrical circuit which deenergizes the rotating means and stops the withdrawal of the strand from the cop.

8. An apparatus for detecting a broken strand being withdrawn from a strand supply cop by a member rotating about the cop, which comprises a post rotatably mounted adjacent to the cop, means provided on the post so as to be engaged by a broken strand to turn the post, and means arranged to be actuated when the shaft is turned to stop the withdrawal of the strand from the cop when a strand break occurs.

9. An apparatus for detecting a broken strand being withdrawn from a strand supply cop by a member rotating about the cop, which comprises a post rotatably mounted adjacent to the strand supply cop, a wire loop positioned on the post so that it extends toward the member withdrawing the strand from the cop, said loop being arranged to turn the post when it is engaged by the end of a broken strand carried by the strand of the strand from the cop when a broken strand occurs. 7

10. An apparatus for tensioning a filamentary material being withdrawn from a supply cop,

which comprises a support having an annular rccess therein, a shaft positioned centrally on the support with respect to the recess, a spindle mounted rotatably on the shaft and designed to carrya cop containing a supply of filamentary material, said spindle having a flange positioned within the annular recess, means rotatable about the axis of the core for withdrawing the filamentary material from the cop and causing rotation of the cop, means for rendering the Withdrawing means operative or inoperative, a brake element provided on the flange of the spindle for retarding the rotation of the spindle as the filamentary material is withdrawn therefrom, said spindle having a predetermined axial movement on the shaft whereby the brake element applies a braking force to the spindle corresponding to the I combined weight of the cop and spindle and withdrawing member, a sensitive switch armaintains a uniform tension on the filamentary material being withdrawn therefrom, and means for admitting a fluid to the annular recess when the strand withdrawing means is rendered inoperative so as to exert a pressure on the upper surface cf-the flange of the spindle, thereby urging said spindle downwardly on the shaft with a force sufficient to stop the rotation of the 00p simultaneously with that of the withdrawing means.

11. An apparatus for tensioning a filamentary material being served around a continuously advancing core, which comprises a support having an annular chamber therein, a shaft vertically positioned on the support concentrically with respect to the chamber and adjacent to the advancing core, a spindle mounted rotatably on the shaft and designed to carry a cop conta ning a supply of filamentary material to be served around the core, means rotatable about the axis of the core for withdrawing the filamentary material from the cop and causing rotation of the cop, means for rendering the withdrawing means operative or inoperative, said spindle having a flange secured thereon for rotation within the annular chamber, a brake element provided on the flange of the spindle so as to slidably engage the bottom of the annular chamber, said spindle being movable axially on the shaft so that the weight of the cop and the spindle on the brake element causes it to retard the rotation of the spindle with a braking force proportional to the weight of the cop and spindle and thereby maintains uniform tension on the filamentary material as the material is expended from a full cop toan empty cop, resilient means mounted invthe annular chamber to urge the spindle upwardly and partially offset the Weight of the spindle so thatthe pressure on the brake element due to the spindle maintains a tension on the material when the cop is substantially exhausted equal to the tension'created by a full cop, and means for admitting a fluid into the annular chamber when the withdrawing means is rendered inoperative so as to exert a pressure on the upper surface of the'fiange on the spindle, thereby urging said spindle downwardly on the shaft to cause the brakeelement to apply a force sufficient to stop the cop and spindle simultaneously with the withdrawing means.

12. An apparatus for tensioning a filamentary material being served around a continuously advancing core, which comprises a rotatable hollow acoaasa shaft vertically positionedso that the core may be advanced longitudinally therethrough, means for rotating the shaft, a tubular spindle mounted rotatably on the shaft and designed to carry a cop containing a supplyoffilamentary material to be served around the core, means rotated by the shaft for withdrawing, the filamentary materialfrom the cop and causingrotation of the cop at a rate of speed substantially faster than that .of the withdrawingmean's,=.a brakeelement secured to the spindle for retarding the rotation of the spindle with respect ,to the withdrawing means, said spindle being movable axially on the shaft so that the combined weight of the cop and the spindle exerts a downward pressurev on the brakeflelementand causes itto' apply braking .forceto the spindle proportional to the combined weight'of the .cop and the spindle whereby a.uniform tension is maintained on lthe filamentary material as it is expended from a full cop to an empty cop, means for rendering the withdrawing means operative'or inoperative, and fluidactuated means operable when the strand withdrawingmeans is rendered inoperative for urging the spindle downwardly on the shaft with a force corresponding to the size of the cop at that timeto cause the'brake element to stop the rotation of the cop simultaneously "with the withdrawingmeans. j

13. ,An apparatus for tensioning a strand ma- 'terial being 'servedaround a continuously advancing filamentary core, which comprises a hollow shaft verticallypositioned so that the core may be advanced longitudinally therethrough, a flange having an annular recess therein secured to the shaft, means for rotating the shaft, a spindle mounted rotatably on the shaiftiand designed to carry a cop containing a supply of strand material to be served'around the core,'a cup secured coaxially on the flange for rotation with the shaft, said cup being designed to withdraw the filamentarymaterial from the cop and serve it spirally around the advancing core andcause rotation of the cop with respect to the flange, means for rendering the shaft rotating means operative or inoperative, said spindle having a flange whose periphery rotatably engage the wall ofthe annular recess, a brake element secured oift'he side'of the flange adjacent to the bottom of the chamber, said spindle being movable axially on the shaft so that the combined weight of the cop and spindle presses the brake element against the bottom of the annular recess and causes it to exert a braking force on the spindle corresponding to the combined weight of the cop and the spindle and thereby maintaining a uniform tension on the filamentary material as it is expended from a full to an empty v cop, and means operable when the shaft rotating means is rendered inoperative for admitting a fluid to the annular chamber under a pressure corresponding to the Weight of the cop at that time so as to exert a pressure on the upper surface of the flange of the spindle, thereby urging said spindle downwardly to cause the brake element to stop the cop when the cup is stopped.

14. An apparatus for tensioning a filamentary material being served around an advancing continuous core, which comprises a hollow vertical shaft through which such a core may be advanced longitudinally, a flange having an annular chamber therein secured centrally on the shaft, means for rotating the shaft, a tubular spindle mounted rotatably on the shaft and designed to carry a cop containing filamentary ma- 18 terial to be served around the core, a cupsecured to the flange for rotation therewith, means provided on the cup for withdrawing the filamentary material from the cop and serving it spirally around the core and causing rotation of the cop, said Withdrawal of the material from the cop causes it to rotate, at a rate of speed substantially faster than that of thecup driven by the shaft, means for rendering the shaft rotating means operative or inoperative, said spindle having a flange positioned within the annular chamber so that its periphery slidaloly engages the walls of the chamber, a brake element secured on the flange adjacent to the bottom of the annular chamber, said spindle being movable axially on the shafts o that the combined weight of the cop and the spindle urge the brake element against the bottom of the annular chamber and causes it to exert a braking force on the spindle corresponding to the combined weight of the cop and spindle as the serving operation proceeds from afull cop to an empty cop, means operable when the shaft rotating means is rendered inoperative for admitting air under pressure to the annular chamber so as to exert a pressure on the upper surface of the flange on the spindle, thereby urging the spindle downwardly on the shaft to increase the pressure on the brake element, and means for controlling the pressure of the fluid in' the annular chamber in accordance with the weight of thecop to bestopped at that time so that the brake element stops the cop simultaneously with thecup. v 1

15. An apparatus for tensioning strand material being withdrawn from a supply cop, which comprises a vertically positioned shaft, a spindle rotatably mounted on the shaft and designed to carry a cop containing a supply of strand material, means for withdrawing the strand material from the cop and causing rotation of the spindle and the cop, means for-applying a braking force to the spindle determined by the Weight of the cop and the spindle and thereby maintaining a uniform tension onthe material as it is expended from afull cop to an empty cop; a detector, arranged to be actuated by a strand travelin outside its normal path of travel around the cop,

and means responsive to the operation of the detector for stopping the withdrawal of the strand from the cop.

16. An apparatus for tensioning filamentary material being withdrawn from a supply cop, which comprises a support, a shaft vertically positioned on the support, a spindle rotatably mounted on the shaft and designed to receive a cop containing a supply of filamentary material, means rotatable about the shaft for withdrawing the filamentary material from the cop and'causing rotation of the cop, a brake element mounted on the spindle so as to slidably engage the support, said spindle being movable axially on the shaft so that the combined weight of the cop and the spindle causes the brake element to apply a braking force on the spindle corresponding directly to the weight of the cop and the spindle as the material is expended from the cop, a detector positioned on the support so as to be actuated by filamentary material extending outside its normal path of travel around the cop, means responsive to the operation of the detector for stopping the withdrawing means, and means operable when the withdrawing means is stopped by operation of the detector for stopping the cop simultaneously with the withdrawing means toprevent overrunning of the cop with respect to the serving means.

, 17. An apparatus for tensioning a strand material being withdrawn from a supply cop, which comprises a vertically positioned shaft, means for rotating the shaft, a support secured centrally on the shaft and having an annular chamber therein, a Ispindle mounted rotatably on the shaft and designed to carry a cop containing a supply of strand material, a cup surrounding the cop and secured for rotation with the shaft for Withdrawing the strand material from the cop and causing the rotation of the cop, said spindle having a flange whose periphery engages the walls of said annular chamber, a brake element secured on the flange so that it engages the bottom of the annular chamber, said spindle being movable axially on the shaft so that the combined weight of the cop and spindle causes the brake element to exert a braking force on the spindle correspondin to the combined weight of the cop and spindle and thereby maintains uniform tension on the strand material as it is expended from the cop, a post mounted rotatably adjacent to the cup and having a wire loop 'extending outwardly toward the cop, a sensitive switch arranged to be actuated when the post is turned, said switch being arranged to control the continuity of an electric control circuit for rendering the shaft rotating means operative or inoperative, said post being so positioned that a strand extending beyond its normal path around the cop strikes the wire loop with sufiicient force to turn the post and actuate the sensitive switch and terminate the withdrawal of the strand material from the cop, means for introducing a fluid under pressure to the annular chamber so as to exert a pressure on the upper surface of the flange on thebrake element thereby urging the spindle downwardly, means for controlling the pressure of the fluid admitted to said annular chamber, and timing mean started simultaneously with the strand withdrawing means for regulating the fluid pressure controlling means so that the fluid admitted to the annular chamber varies the braking force applied to the spindle by the brake element by an amount corresponding to the size of the cop to be stopped,

when astrand actuates the' sensitive switch in order to prevent 'overrunnin'g ofthe cup with respect to the cup. 9 p r V 18. A brake for tensioning strands withdrawn from a supply cop provided on strand handling apparatus, which comprises asupport, a shaft vertically positioned on the support, a spindle rotatably mounted on the shaft and designed to carry a cop containing a supply of strand material, means rotatable'about the cop for withdrawing the 'material'from thecop and causing rotation of the cop, means for rendering the withdrawing means operative or inoperative, a brake element mounted on the spindle so as to engage the support, said" spindle being free'to move axially on the shaft'so that the combined weight of the cop and the spindle causes the brake element to retard the rotation thereof with a force corresponding directly to the weight of the cop and ther'eby 'maintain constant ten-- sion on the material as it -is expended from a full cop to an empty cop, a detector arranged to be actuated by a strand extending outside its normal path of travel with respect to the withdrawing means, means responsive to the operation of the detector for stopping the strand withdrawing means, and fluid actuated means for urging the spindle downwardly on the sh'aft'so as to increase the braking force exerted'by the brake element on the spindle sufiiciently to stop the cop-simultaneously with the strand withdrawing means. J i v H TILLMAN T. BUNCH.

' REFERENCES CITED The following refe'renc'es are ofre'co'rd-in the file of this patent:

UNITED STATES PATENTS V Date 

